Directional control valve assembly



United States Patent Inventor Hugh J. Stacey Willoughby, Ohio Appl. No.769,610

Filed Oct. 22, 1968 Patented Dec. 1, 1970 Assignee Parker-Hannii'mCorporation Cleveland, Ohio a corporation of Ohio DIRECTIONAL CONTROLVALVE ASSEMBLY 18 Claims, 4 Drawing Figs.

US. Cl 91/411; 60/52.60/97:137/596.l7

Int. Cl. FlSb 13/06 Field of Search 91/41 1,

411(A), 41l(Al);60/97(E), 52(US), 52(HE), 97(H); l37/596.l7 (lnquired)[56] References Cited UNITED STATES PATENTS 1,900,050 3/1933 Ernst60/97(E)UX 2.669.941 2/1954 Mueller 60/52(US) 2,800,l 1 l 7/1957 Schnurret al. 60/97(E)UX 3,173,259 3/1965 Harbidge 60/97(E)X 3,426,650 2/l969Jenney 91/41 1X Primary Examiner-Edgar W. Geoghegan Attorney0berlin,Maky, Donnelly & Renner ABSTRACT: A directional control valve assemblyfor actuating a pair of fluid motors (or pairs of fluid motors)characterized in that duplicate directional control valves haveduplicate motor ports adapted to be connected to the respective fluidmotors and have duplicate inlet ports adapted to be connected toduplicate pumps, said inlet ports and/or the respective motor ports ofsaid valves being cross-connected thus to equalize the fluid pressuresin said inlet ports and/or in said motor ports to provide substantiallyequalized flow of fluid to the respective motors.

DMECTIIONAL CONTROL VALVE ASSEMBLY BACKGROUND OF THE INVENTION Inhydraulic power systems for presses, machine tools, hoisting equipment,etc. it is sometimes desirable or necessary to provide a pair of fluidmotors to actuate a press ram, a machine tool slide, a hoist boom, etc.rather than a single large size fluid motor. In such dual motorinstallations it is known to employ one large size pump (or a pluralityof smaller pumps) having a capacity to supply fluid at required pressureto both motors via a single large size directional control valveassembly and large size conduits or hoses connected to the motor portsof the directional control valve, said conduits or hoses terminating attees for splitting the flow of fluid to the respective motors.

It is also known to provide a dual directional controlvalve assembly foreach pair of motors, but here again, a large size valve assembly isrequired to handle the total flow of the large size pump (or of aplurality of smaller pumps) through its inlet and return ports andthrough its bypass passage. Furthermore, because one valve member isupstream of the other, the simultaneous actuation of the valve memberswill result in the motor associated with the downstream motor portreceiving a lower pressure than the motor associated with the upstreammotor port due to the greater pressure drop through the valve passagesleading to the downstream motor port and thus the motors tend to applytwisting or cocking strains on the guides of the component actuatedthereby.

It is also well known to provide complex synchronizing means orproportional flow dividers in hydraulic systems which generally areactuated by the pistons of the respective motors to achieve synchronizedoperation of the motors.

- SUMMARY OF THE INVENTION With the foregoing in mind it is a principalobject of this invention to provide a directional control valve assemblywhich has duplicate inlet ports for connection to duplicate pumps,duplicate motor ports. for connection to duplicate motors, and duplicatevalve members which are simultaneously actuated to open and close fluidcommunication between the respective inlet ports and motor ports, theports, valve members, and conduits being of size to accommodate thefluid flow required for the respective motors. In addition, the inletports and/or the motor ports are cross-connected to each other toequalize the pressures in the inlet ports and/or in the motor portswhereby said motors will be operated in synchronism.

Other objects and advantages of the present invention will becomeapparent as the following description proceeds.

To the accomplishment of the foregoing and related ends, the invention,then, comprises the features hereinafter fully described andparticularly pointed out in the claims, the following description andthe annexed drawing setting forth in detail a certain illustrativeembodiment of the invention, this being indicative, however, of but oneof the various ways in which the principle of the invention may beemployed.

BRIEF DESCRIPTION OF THE DRAWING In the annexed drawing:

, 2. DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now in detail tothe drawing, FIG. 1 illustrates a hydraulic system comprising areservoir l, a pair of pumps 2;2 for supplying fluid under pressure tothe respective inlet ports 3;3 of a directional control valve assembly4, and a pair of fluid motors 5;5 connected as shown to the respectiveupper pairs of motor ports 6;6 of said valve assembly 4. The directionalcontrol valve assembly 4 also has a pair of return ports 7;7 which areconnected as shown to the reservoir 1. As evident from FIGS. 2 and 45,the directional control valve as sembly 4 also has lower pairs of motorports 8;8 adapted for connection with another pair of fluid motors (notshown).

The directional controlvalve assembly.4 herein shown for purpose ofillustration comprises two double-spool directional control valves 9;9which are bolted together with a plate Ill therebetween. The upperspools ll;l]l of the respective valves 9;9 are connected together forsimultaneous actuation by a yoke 12 and if desired, or necessary, theyoke 12 may be actuated through a pneumatic or hydraulic power assistunit 14 which is supported on a bracket 15 attached to the valveassembly 4. The lower pair of spools 16;16 are similarly connectedtogether by a yoke 12 actuated by a power assist unit Ml.

Each double-spool valve 9 comprises a housing 17 having an inlet port 3,a return port 7, and a bypass passage 18 for flow of fluid from theinlet port 3 to the return port 7 when both spools 11 and 16 are inneutral position as shown in FIG. 2

Each housing 17 has parallel bores 11 and 16' in which the respectivespools 11 and 16 are reciprocable, said bores being FIG. 1 is a top planview of a directional control valve assembly embodying the presentinvention, the same being shown in a hydraulic system employing twopumps for synchronous operation of a pair of fluid motors connected tothe respective upper pairs of motor ports of said valve assembly;

FIG. 2 is across-sectional view taken substantiallyalong the line 2-2,FIG. l;

FIG. 3 is a cross-sectional view taken substantially along the line 3-3,FIG. 2; and

FIG. t is a cross-sectional view taken substantially along the line 4-4,FIG. 2.

intersected by the aforesaid bypass passage 18, by pressure feedpassages 19;19, motor passages 6;6' and 82% communicating with therespective motor ports 6;6 and 8;8 and by return passages 7 ;7' leadingto the return port 7. Each housing 17 also has another bore 20 upstreamof the upper spool 11 in which is contained a relief valve 21 whichconducts excess pressure in the system from the inlet port 3 and inletchamber 3' to the return port 7 via a return passage 7'.

As shown in FIGS. 3 and 4, the bypass, pressure feed, motor, and returnpassages 18, 19, 6', 8', and 7' of each housing 17 have lateralextensions which intersect bores 2323 parallel to the respective spoolbores Ill and 16', there being a pair of check valves 24;24 in each bore23.

The spools 11.;11 (and also spools l6;16) herein shown are of thefour-way type for actuating the respective doubleacting fluid motors 5;5whereby when the upper spools ll are shifted to the left from theneutral position shown in FIG. 2 through the upper yoke 12 and powerassist unit 14, the right pressure feed passages 19 are communicatedwith the right motor passages 6' and ports 6 thus to conduct fluid underpressure from the respective inlet ports 3 into the head ends of therespective motors 5, and the left motor passages 6' and ports 6 arecommunicated with the left return passages 7 whereby fluid displacedfrom the rod ends of the motors 5 is conducted to the respective returnports 7. Conversely, when the upper spools 11 are shifted to the rightfrom FIG. 2 neutral position, the left pressure feed passages 19 arecommunicated with the left motor passages 6' and ports 6 and the rightmotor passages 6' and ports 6 are communicated with the right returnpassages 7 whereby the fluid motors 5 will be actuated in the oppositedirection by fluid under pressure entering the rod ends thereof and thedisplaced fluid being conducted to the reservoir 1 from the head endsthereof via the right motor ports and passages 6 and 6' and right returnpassages and ports 7' and 7.

As previously mentioned, the valves 9 containing the upper and lowerspools 11 and 16 are duplicates of each other and are fastened back toback with a plate 10 therebetween. As clearly shown in FIGS. 3 and 4,the plate 10 and the respective housings l7 have registering passages 25which intercommunicate the respective inlet ports and passages and 3 and3' and registering pairs of passages 2636 and 27;27 which respectivelyinter-communicate motor ports and passages 6;6 and 6;6' and the motorports and passages ;8 and 8';8'. By reason of such cross-connections,the motors (or the motors associated with the lower pairs of motor ports833) will be operated in synchronism because the fluid pressures arebalanced or equalized in the inlet ports and passages 3 and 3' and inthe motor ports and passages 6 and 6 which are then pressurized. inother words, the motors 5 receive equal actuating pressures.

From the foregoing discussion, it can now be seen that the flow pathsthrough the directional control valves 952* for each pair of motors 55are identical and since the pressures are equalized by cross-connectionsthrough plate ill), the respective motors 5 will operate in synchronismin the actuation of a movable component of a press, a machine tool,hoisting equipment, etc. Although it is preferred herein to employdoublespool directional control valves 9;9 each arranged forseriesparallel operation wherein only one spool ill or 16 thereof may beactuated, it is to be understood that each double-spool valve 9 may bearranged for parallel operation wherein both spools ill and 16 may beactuated simultaneously.

lclaim:

l. A valve assembly comprising a housing having duplicate inlet andmotor ports; duplicate valve members in said housing and actuating meanstherefor operable to simultaneously move said valve members to open andclose communication between the respective inlet and motor ports; saidhousing having a passage therein intercommunicating said inlet portswith each other thus to substantially equalize fluid pressures in saidinlet ports for substantially equalized flow of fluid to fluid motorsadapted to be connected to the respective motor ports.

2. A valve assembly comprising a housing having duplicate inlet andmotor ports; duplicate valve members in said housing and actuating meanstherefor operable to simultaneously move said valve members to open andclose communication between the respective inlet and motor ports; saidhousing having a passage therein intercommunicating said motor portswith each other thus to substantially equalize fluid pressures in saidmotor ports when said valve members are moved to open communicationbetween the respective inlet and motor ports for substantially equalizedflow of fluid to fluid motors adapted to be connected to the respectivemotor ports.

3. A valve assembly comprising a housing having duplicate inlet andmotor ports; duplicate valve members in said housing and actuating meanstherefor operable to simultaneously move said valve members to open andclose communication between the respective inlet and motor ports; saidhousing having first and second passages therein respectivelyintercommunicating said inlet ports with each other and said motor portswith each other thus to substantially equalize fluid pressures in saidinlet ports and in said motor ports for substantially equalized flow offluid to fluid motors adapted to be connected to the respective motorports.

4. A valve assembly comprising a housing having duplicate inlet ports,duplicate pairs of motor ports, and at least one return port; duplicatevalve members in said housing and actuating means therefor operable tosimultaneously move said valve members from a neutral position whereatsaid inlet ports are communicated with said return port to an operatingposition whereat one of each pair of motor ports is communicated withthe respective inlet port and the other of each pair of motor ports iscommunicated with said return port; said housing having a passagetherein intercommunicating said inlet ports with each other thus tosubstantially equalize fluid pressures in said inlet ports forsubstantially equalized flow of fluid to fluid motors adapted to beconnected to the respective pairs of motor ports.

5. A valve assembly comprising a housing having duplicate inlet ports,duplicate pairs of motor ports, and at least one return port; duplicatevalve members in said housing and actuating means therefor operable tosimultaneously move said valve members from a neutral position whereatsaid inlet ports are communicated with said return port to an operatingposition whereat one of each pair of motor ports is communicated withthe respective inlet port and the other of each pair of motor ports iscommunicated with said return port; said housing having a passagetherein intercommunicating said one motor ports with each other tosubstantially equalize fluid pressures in said motor ports forsubstantially equalized flow of fluid to fluid motors adapted to beconnected to the respective pairs of motor ports.

6. A valve assembly comprising a housing having duplicate inlet ports,duplicate pairs of motor ports, and at least one return port; duplicatevalve members in said housing and actuating means therefor operable tosimultaneously move sai valve members from a neutral position whereatsaid inlet ports are communicated with said return port to an operatingposition whereat one of each pair of motor ports is communicated withthe respective inlet port and the other of each pair or" motor ports iscommunicated with said return port; said housing having first and secondpassages therein respectively intercommunicating said inlet ports andsaid one motor ports with each other thus to substantially equalizefluid pressures in said inlet ports and in said one motor ports forsubstantially equalized flow of fluid to fluid motors adapted to beconnected to the respective pairs of motor ports.

7. A valve assembly comprising a housing having duplicate inlet ports,duplicate pairs of motor ports, and at least one return port; duplicatevalve members in said housing and actuating means therefor operable tosimultaneously move said valve members from a neutral position whereatsaid inlet ports are communicated with said return port to operatingpositions whereat the motor ports constituting each pair of motor portsare selectively communicated with the respective inlet port and saidreturn port to control the direction of actuation of double-acting fluidmotors adapted to be connected to the respective pairs of motor ports;said housing having first, second, and third passages thereinrespectively intercommunicating said inlet ports, one of each pair ofmotor ports, and the other of each pair of motor ports with each otherthus to substantially equalize fluid pressures in said inlet ports, saidone motor ports, and said other motor ports for substantially equalizedflow of fluid to and from such fluid motors.

S. A valve assembly comprising a pair of housings providing duplicateinlet ports, motor ports, and return ports; duplicate valve membersmovable in the respective housings selectively to establish fluidcommunication of the respective motor ports with the respective inletports and with the respective return ports; actuating means operativelyconnected with said valve members to effect simultaneous movement of thelatter; and cross-connection means associated with said housings havinga first passage intercommunicating said inlet ports with each other tosubstantially equalize fluid pressures in said inlet ports forsubstantially equalized flow of fluid to fluid motors adapted to beconnected to the respective motor ports.

9. The valve assembly of claim 8 wherein said cross-connection means hasa second passage intercommunicating said motor ports with each other forsubstantially equalized flow of fluid to or from such fluid motors.

ill. The valve assembly of claim 8 wherein said cross-connection meanscomprises a platelilte member clamped between 33 said housing and havingsaid first passage therethrough registering with passages in therespective housings leading to the respective inlet ports.

Ill. The valve assembly of claim 9 wherein said cross-connection meanscomprises a platelike member clamped between said housings and havingsaid first and second passages therethrough respectively registeringwith passages in said housings leading to the respective inlet ports andmotor ports.

112. A valve assembly comprising a pair of housings providing duplicateinlet ports, duplicate pairs of motor ports adapted for connection withdouble-acting fluid motors, and duplicate return ports, duplicate valvemembers movable in the respective housings selectively to establishfluid communication between the respective inlet ports, pairs of motorports,

and return ports for actuating such fluid motors in opposite directions;actuating means operatively connected with said valve members to effectsimultaneous movement of the latter; and cross-connection meansassociated with said housings having a first passage intercommunicatingsaid inlet ports with each other to substantially equalize fluidpressure in said inlet ports for substantially equalized flow of fluidto such fluid motors.

13. The valve assembly of claim 12 wherein said cross-connection meanshas a pair of second passages intercommunicating the motor portsconstituting the respective pairs of motor ports with each other forsubstantially equalized flow of fluid to and from such fluid motors.

M. The valve assembly of claim 12 wherein said housings have duplicatebypass passages leading from the respective inlet ports to therespective return ports; and wherein said valve members when moved asaforesaid close the respective bypass passages.

15. in a fluid pressure system, the combination of a reservoir',duplicate pumps; a valve assembly having duplicate inlet ports,duplicate pairs of motor ports, and duplicate return ports, duplicatevalve members movable in said assembly and actuating means thereforoperative to simultaneously move said valve members to operatingpositions whereat the motor ports constituting the respective pairs ofmotor ports are selectively communicated with the respective inlet portsand return ports; duplicate double-acting fluid motors; conduit meansconnecting said pumps to said reservoir and to the respective inletports, connecting said motors to the respective pairs of motor ports,and connecting said return ports to said reservoir whereby upon movementof said valve members said motors are actuated in desired direction; andcross-connection means providing a first passage which intercommunicatessaid inlet ports with each other to substantially equalize fluidpressures in said inlet ports for substantially equalized flow of fluidto the respective motors.

16. The system of claim 15 wherein said cross-connection means providesa pair of second passages which intercommunicates the respective pairsof motor ports with each other further to substantially equalize flow offluid through said motor ports to and from the respective motors.

17. A valve assembly comprising: a pair of valve housings securedtogether with a plate member therebetween; each housing having a boreintersected by passages leading respectively to an inlet port, a returnport, and the respective ones of a pair of motor ports; parallel valvespools reciprocable in the respective bores from a neutral positionwhereat said inlet ports are in fluid communication with the respectivereturn ports to operating positions whereat said inlet ports and returnports are selectively in fluid communication with the respective pairsof motor ports; actuating means operatively connected to said valvespools to simultaneously reciprocate the same; said plate member andhousings having registering passages which intercommunicate said inletports with each other thus to substantially equalize fluid pressurestherein for substantially equalized flow of fluid to a pair ofdouble-acting fluid motors adapted to be connected to the respectivepairs of motor ports.

18. The valve assembly of claim 17 wherein said plate member andhousings have additional registering passages which intercommunicate therespective pairs of motor ports with each other.

